Cheaper, Smaller Solar
The two main knocks on solar power today are that it is still expensive, on either a per kilowatt of capacity or per kilowatt-hour of delivered electricity basis, and that to get the cost down for the power you need, you have to cover large areas with solar cells of lower efficiency.
Technology Review recently reported on a new approach that would reduce both cost and the area entailed, by cheaply increasing the cell's efficiency. We already know how to make multi-bandgap solar cells that capture up to 36% of the light energy that shines on them, but these tend to be reserved for applications such as NASA's Spirit and Opportunity space probes, where the collection area available is at a premium and for use where the sun shines more faintly. But they are also quite expensive.
Being able to apply the same approach at even higher efficiencies, but at much lower cost, would improve solar's cost-competitiveness relative to other technologies and allow it to compete for applications that are currently impractical, due to size constraints. And in larger-scale installations, such as for distributed power, the same effect would reduce the environmental and aesthetic impact of the project.
As the article points out, more work is required, but this could be a big deal in a few years.